As one of conventional massage devices capable of massaging lower legs (between below-knee and ankle regions, in particular) of a user, there is known a massage device implemented in a footrest of a chair-type massage apparatus (Patent Literature 1, for example). This massage device has a pair of right-hand and left-hand treatment recesses, and an air bag is disposed on each of the opposite spaced inwardly-directed side surfaces, as well as on both sides of the intermediate wall, of the paired recesses. The air bags are each inflated and deflated by an air supply-exhaust unit, thereby massaging the lower legs put in their respective treatment recesses at the same time.
In general, an air bag is so inflated that its dimension increases to a maximum at the midportion, and decreases gradually with approach toward each end. Therefore, a sufficiently high pressing force is exerted only in a narrow range of the lower leg in its lengthwise direction. With this in view, there is proposed a massage device equipped with a plurality of air bags juxtaposed in a direction longitudinally of each treatment recess, for massaging lower legs over a wide area in the lengthwise direction by supplying air to and exhausting air from the air bags concurrently or sequentially (Patent Literature 2, for example).
By way of contrast, there is proposed a massage device that employs, instead of an air bag, a mechanism for moving opposite wall portions constituting a treatment recess close to and away from lower legs (Patent Literature 3, for example).